A gas turbine engine typically includes a fan section, a compressor section, a combustor section, and a turbine section. Air moves into the engine through the fan section. Airfoil arrays in the compressor section rotate to compress the air, which is then mixed with fuel and combusted in the combustor section. The products of combustion are expanded to rotatably drive airfoil arrays in the turbine section. Rotating the airfoil arrays in the turbine section drives rotation of the fan and compressor sections.
The gas turbine engine may have various gas-flow streams that may be kept separate from one another by various components and/or seals. Brush seals may be employed in applications where the seal cavity, within which the brush seal is located, expands and contracts axially due to translation and/or thermal expansion of the components that define the seal cavity. Brush seals may also be employed in applications where there is a high pressure differential between the various gas-flow streams. However, in applications challenged by both axial expansion/contraction and high pressure differentials, current brush seal designs tend to experience difficulties, as brush seals with large backing plate gaps are generally needed for active seal cavities (i.e., seal cavities that experience expansion and contraction) to prevent the backing plate from contacting the axial surfaces of the seal cavity. However, in high pressure differential applications, large backing plate gaps tend to lead to increased bristle blow-over, which may lead to leakage at the sealing interface.